The following U.S. Patents describe prior art relevant to the subject invention.
U.S. Pat. No. 4,103,738 discloses a heat exchanger having a plurality of replaceable tubes disposed in a bulk-head at the inlet side of the heat exchanger, which tubes are adapted to be readily replaced after sustaining excessive wear due to flow of a fluid containing an abrasive.
A leak protected heat exchanger is disclosed in U.S. Pat. No. 3,825,061 in which headers at opposite ends of flow passages through a heat exchanger form leak chambers which are drained by connected tubing to prevent mixing of a first and a second fluid should a joint failure occur. The flow passages extend from the core and through the leak chambers at each end of the heat exchanger.